Fires are classified as A, B, C or D as follows: Class A: ordinary combustibles; Class B: flammable liquids; Class C: electrical fires and Class D: flammable metals. Fire extinguishers are certified in Canada and the United States by ULC and UL respectively according to their effectiveness in suppressing the fires of the various classes. A standard extinguisher with an A:B:C rating for example, is effective in suppressing A, B and C class fires.
To achieve an A:B:C rating, extinguishers to date have used either dry chemicals or halon. The use of dry chemicals results in a messy and sometimes toxic cleanup. Halon is a clean alternative but has been banned by the Montreal Protocol on Substances that Deplete the Ozone Layer.
Water has also been used but prior art water extinguishers have not achieved an A:B:C rating. The standard water extinguisher for example discharges a solid stream of water from a pressurized canister and has a limited Class 2A rating.
Another type of known water extinguisher discharges a spray of water droplets and utilizes the same amount of water as the standard extinguisher. This extinguisher typically operates at about 100 psi. While this water extinguisher has been rated A:C, it does not generate the fine atomized mist required for a class B rating.
It is a feature of the present invention to provide an extinguisher in which water and air are stored together and released simultaneously and separately to produce a fine liquid mist, capable of class A:B:C rating.